JeremyW wrote:A cool document from the CAISO on updating the time of use periods can be found here.

SDG&E switched to basically these TOU periods in December. It's doubled the amount of money I now pay for electricity annually.

Definitely need to do more analysis if battery storage makes sense, but my initially calculations only made it marginal at best at current rates, but that probably means that it will be a no-brainer 5 years from now with the way rates are going.

We switched to a TOU program two months ago. Our bill is now a third of what it was. BUT...in the winter we live in our motorhome on our property in Palm Springs. At 8 o;clock we switch the coach to battery and let the inverters do the work. At 10 at night we switch it back. Went from a 115 dollar per month bill to 36. We have 800 watts of solar on the roof. Works well. Kinda like a power wall but not. 8 x 6 volt batteries.

I was able to find a SCE Rate Comparison Tool mentioned by Boomer23 at breakfast last Saturday. It supposedly allows you to evaluate and compare several of the new and old TOU rates against your actual usage for the previous 12 months. Of course if you are contemplating adding solar or another EV, this evaluation will be flawed, but if your usage is stable, it should help a lot.

There are several paths on the web site to this tool. One is: home (residential) -> rates are changing -> learn more -> Residential Rate Plans -> Rate Comparison Tool.

I say "supposedly" because I could not run the tool. It requires a customer account of the form: 3-###-####-##. My customer account has the form: 2-##-###-####, so the tool rejects it. Is this because I am already on TOU-D-A ? I believe others on this thread also have TOU-D-A. Do you also have a 2-## account ?

I am overwhelmed with all the TOU choices, but some of them can be eliminated right away if you have solar, because they price daytime at Off-peak or Super Off peak (TOU-D-4-9PM, TOU-D-5-8PM).

When I was sizing my solar system I had to write a little program that could crunch my hourly usage data from SCE for the last 12 months against estimated solar hourly production for a year from the pvwatts estimator. I could plug-in different TOU schedules to get an idea how things would work out.

Valdemar wrote:When I was sizing my solar system I had to write a little program that could crunch my hourly usage data from SCE for the last 12 months against estimated solar hourly production for a year from the pvwatts estimator. I could plug-in different TOU schedules to get an idea how things would work out.

Interesting - in our area there is a provider that bills us based on 15 minute interval actual pricing (energy, not distribution) - for a monthly subscription price ($10). Did you download this type data and crunch it out off-line, or can you do this more or less real time by capturing data, say on an hourly/daily interval? What is astonishing is that some "peak" pricing is 10X "normal" and that "off peak" pricing can actually be a payment rather than a cost!

Also amazing is that so many in my area use copious amounts of energy (pools, kids with doors open/lights on, etc, etc). If they installed a well designed solar system with properly sized energy storage that is bi-directional (Pika Energy) with "smart" usage controls, they could pay back much of the system costs. Having an EV to charge early morning would enhance their savings - especially if they purchase a used Leaf (for next to nothing ). IMO, change is coming!

It was offline, downloaded 12 months usage history at X minute intervals in CSV format, the value X is escaping me at the moment but at least on an hourly basis if not more granular. Similar for pvwatts estimated production. There should be a software package out there that can do similar calculations, but I couldn't find anything at the time. It worked out pretty close to my prediction, I'm about 3,000kWh net consumer over 12 months and pay $0 not counting mandatory fees. The system is a tad larger than I could have gotten away with but that was a conscious decision. Of course this is only true until SCE changes the TOU rates which may send all my projections down the drain.

That is a real worry - as more pure grid tied energy systems go on-line, any use of the grid as storage may not be cost effective. Battery storage can work around this issue - especially if I could get my Leaf to be the "storage" - may be coming.